Superficial desmoplastic fibroblastoma (collagenous fibroma): Clinicopathologic study of 11 cases.

BACKGROUND: Desmoplastic fibroblastoma (collagenous fibroma) is a rare soft tissue tumor that usually arises in the subcutis or skeletal muscle. Cases superficial to fascia are unusual and can cause diagnostic difficulty. We present 11 cases of superficial desmoplastic fibroblastoma involving a wide anatomic distribution. METHODS: Archives were searched using the term "desmoplastic fibroblastoma" over a 10-year period (2012-2022). Cases superficial to fascia were retrieved, and available clinicopathologic features were recorded. Only cases involving the dermis were included. RESULTS: Eleven cases were identified, all of which were received in consultation. Tumors involved the head and neck (2), lower extremity (2), back (2), foot (1), shoulder (1), axilla (1), hand (1), and breast (1). Each consisted of a hypocellular proliferation of bland stellate to spindled fibroblasts set in a collagenous to focally myxoid stroma. The immunohistochemical stains available for review demonstrated SMA positivity (4/7) and negative immunoreactivity for CD34 (0/6), EMA (0/3), desmin (0/3), and S100 (0/7). CONCLUSIONS: Desmoplastic fibroblastoma may present superficially in the dermis to subcutis, posing a potential source of diagnostic difficulty. Recognition of the characteristic histopathologic features of desmoplastic fibroblastoma with judicial use of immunohistochemical stains should allow for accurate diagnosis.

Recurrent FOSL1 rearrangements in desmoplastic fibroblastoma.

The FOS gene family has been implicated in tumourigenesis across several tumour types, particularly mesenchymal tumours. The rare fibrous tumour desmoplastic fibroblastoma is characterised by overexpression of FOSL1. However, previous studies using cytogenetic and molecular techniques did not identify an underlying somatic change involving the FOSL1 gene to explain this finding. Prompted by an unusual index case, we report the discovery of a novel FOSL1 rearrangement in desmoplastic fibroblastoma using whole-genome and targeted RNA sequencing. We investigated 15 desmoplastic fibroblastomas and 15 fibromas of tendon sheath using immunohistochemistry, in situ hybridisation and targeted RNA sequencing. Rearrangements in FOSL1 and FOS were identified in 10/15 and 2/15 desmoplastic fibroblastomas respectively, which mirrors the pattern of FOS rearrangements observed in benign bone and vascular tumours. Fibroma of tendon sheath, which shares histological features with desmoplastic fibroblastoma, harboured USP6 rearrangements in 9/15 cases and did not demonstrate rearrangements in any of the four FOS genes. The overall concordance between FOSL1 immunohistochemistry and RNA sequencing results was 90%. These findings illustrate that FOSL1 and FOS rearrangements are a recurrent event in desmoplastic fibroblastoma, establishing this finding as a useful diagnostic adjunct and expanding the spectrum of tumours driven by FOS gene family alterations. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Desmoplastic Fibroma of Radius Managed with Non-Vascularised Fibular Autograft - A Case Report.

Desmoplastic fibromas of bone are extremely rare, slow growing, locally invasive, benign primary bone tumours, bearing close resemblance to the extra-abdominal desmoid tumours of soft tissue. They typically occur in patients around 30 years of age, and most commonly affect the mandible, pelvis and meta-diaphyseal region of long bones. En bloc or wide resection has typically been the treatment of choice to avoid recurrence, however, recent reports support curettage with bone grafting and adjuvant therapy to minimise functional loss. We report a 9-year-old child with a desmoplastic fibroma of right radius. This is an unusual age group for this bone tumor. The tumor was managed with en bloc resection and reconstruction with a non-vascularised fibula autograft. The patient had good functional outcome and no recurrence at 1-year follow-up. Level of Evidence: Level V (Therapeutic).

FDG PET/CT and Bone Scintigraphy in Desmoplastic Fibroma of the Bone.

ABSTRACT: Desmoplastic fibroma is a very rare benign bone tumor with local aggressiveness. We describe imaging findings in 2 cases with desmoplastic fibroma of the bone. One case had a desmoplastic fibroma in the right distal femur, showing bone destruction with sclerotic margins and inhomogeneous FDG uptake. The other case had a desmoplastic fibroma in the left ninth rib, showing progressive peripheral enhancement and increased 99m Tc-MDP uptake.

Clinical and Imaging Features of Desmoplastic Fibroma of Bone for Correct Diagnosis and Differentiation.

OBJECTIVE: The objective of this study is to analyze the clinical and imaging features of desmoplastic fibroma of bone (DFB) for correct diagnosis. MATERIALS AND METHODS: Twenty patients with DFB confirmed by pathology were enrolled, and the imaging presentations were analyzed. Among 20 patients, plain X-ray was performed in all patients, computed tomography (CT) was performed in 12, and magnetic resonance imaging (MRI) was conducted on eight. The clinical and imaging presentations were analyzed and classified to assist in correct diagnosis. RESULTS: Twenty patients with DFB were retrieved, including eleven males and nine females with an age range of 2-52 years (median 27). The DFB involved the femur in six patients, ilium in five, tibia in four, humerus in two, lumbar vertebra in one, radius in one, and calcaneus in the remaining one. DFB was common in the metaphysis of long bones and could involve the diaphysis and epiphysis. The imaging presentations were divided into four types: the cystic expansile destruction in ten patients, osteolytic destruction in five, mixed destruction in four, and paraosseous destruction in one. CT value was 30 -60 Hu in the lesion area (6 cases CT value45Hu). In eight patients with MRI scanning, the lesion in five patients presented with unevenly equal or low signal on T1WI and unevenly equal or high signal on T2WI, with irregular stripes or patches of low signal on both T1WI and T2WI. In the rest three patients, the lesion was evenly equal or low signal on T1WI and evenly high signal on T2WI. MRI more clearly showed a mass in the adjacent soft tissue and the range of edema in the DFB lesion. CONCLUSION: DFB is a rare tumor with strong local aggressiveness, cystic bone destruction, formation of tumor bone trabeculae, soft tissue masses on imaging presentations, low signals on T1WI and T2WI in the lesion, but no periosteal reaction or calcification, which are helpful for diagnosis of the disease and differentiation from other ones.

Desmoplastic fibroma of the Mandible with unusual histopathological features.

Desmoplastic fibroma (DF) is a rare myofibroblastic primary tumor of bone that histologically and biologically mimics the extra-abdominal desmoid tumor of soft tissue. The surgical management of this tumor has been a matter of controversy and its recurrence has been a matter of clinical relevance. In this case report, we describe an unusual case of DF in a 15-year-old male patient who presented with a slow-growing mass in the right posterior mandibular region of 2 years duration. The presence of areas mimicking Giant cell angiofibroma (GCA) is the highlight of the case. The possibility of misdiagnoses is more in early lesions since the available literature shows that immunohistochemistry (IHC) is not of much benefit while differentiating DFs from other spindle cell lesions.

Tumor de rápido crecimiento en el primer dedo del pie derecho / Rapidly Growing Tumor on the Left Big Toe

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Desmoplastic Fibroblastoma: An Uncommon Tumor With a Relatively Characteristic MRI Appearance.

OBJECTIVE. We undertook this study to determine the radiologic features of desmo-plastic fibroblastoma. MATERIALS AND METHODS. We reviewed available radiologic images for 29 pathologically confirmed desmoplastic fibroblastomas, including images from MRI, radiography, ultrasound (US), and CT. RESULTS. The patient population included 14 women and 15 men (mean age, 60 years; range, 23-96 years). Typically, lesions were oval or lobulated and relatively small (mean, 5.6 cm). In 14 of the 22 cases that included patient histories, lesions had grown slowly, with two eventually causing pain. The remaining eight were discovered incidentally. All lesions involved or were below the deep fascia. Lesions were well-defined and associated with muscle (45%), deep fascia (28%), joint (21%), or tendon (7%). MR images were available in 26 cases; 14 included unenhanced and contrast-enhanced studies. On MRI imaging all lesions were well-defined and adjacent to dense connective tissue. On T1-weighted images, lesions showed varying amounts of low and intermediate signal intensity similar to that of tendon and skeletal muscle, respectively. On fluid-sensitive images, lesions were more heterogeneous, generally showing a wider spectrum of decreased to intermediate signal intensity. On contrast-enhanced MR images, enhancement was characteristically peripheral and septal with patchy areas of homogeneity. In the 10 cases with radiographs, images showed negative findings or a nonmineralized mass. The 10 available ultrasound studies showed mixed echogenicity. In eight patients, unenhanced CT showed lesions having attenuation similar to that of skeletal muscle. CONCLUSION. Desmoplastic fibroblastoma is an uncommon neoplasm with a relatively characteristic MRI appearance.

Does a Vertebra Fracture Cause a Tumor? A Dorsolumbar Paraspinal Desmoid Tumor: Case Report

Extraabdominal desmoid tumors are uncommon soft-tissue tumors. The etiology of the tumor is still unclear. Injury is one of the etiological factors of soft-tissue tumors. A 41-year-old female patient who had a traumatic vertebral body fracture on the thoracic spine was treated conservatively. Two and a half years later, she presented a painful, palpable swelling on the thoracolumbar region. In the present report, was discuss the patient, who underwent a surgery to remove the desmoid tumor (aggressive fibromatosis), within the context of the current literature. The literature on desmoid tumor caused by a trauma is rare. This is the first case that demonstrates an extraabdominal desmoid tumor following a spinal fracture. The swelling on the region of the trauma must be examined carefully and desmoid tumor must be kept in mind as a possible diagnosis.

Desmoplastic fibroma of the mandible: a rare gnathic bone tumor with a review of the literature

Desmoplastic fibroma (DF) is a rare bone tumor, which is known to involve mostly the gnathic bones. In this setting, the clinical presentation is usually represented by a bulging tumor of the face. Radiologically, the tumor is usually characterized by an expansile lytic bone lesion. The histopathology of the tumor shows a poorly circumscribed hypocellular lesion rich in collagen fibers with interspersed spindle cells having bland nuclear chromatin. Despite the lack of mitoses and nuclear pleomorphism, DF has an aggressive nature, presenting as a destructive growth causing entrapment of neuro-vascular bundles, sinusitis, or trismus. Some cases of DF show mutations in the adenomatous polyposis coli pathway shown by nuclear localization of the ß-catenin protein. Few reports showed an association with tuberous sclerosis, though most of these cases were sporadic. We discuss a rare case of desmoplastic fibroma involving the mandible, and a review of the literature of the DF cases involving the gnathic bones.

Desmoplastic Fibroma: A Rare Pathological Midshaft Femoral Fracture Treated With Resection, Acute Shortening, and Re-lengthening: A Case Report.

CASE: We report a rare case of desmoplastic fibroma (DF) of the midshaft femur presenting as a pathological fracture. This rare benign bone tumor was treated with an acute en bloc excision and femoral shortening over an intramedullary nail. Once union of the acute shortening had been achieved, further surgery was undertaken to lengthen the femur with the use of Intramedullary Skeletal Kinetic Distractors. At 3 years after fracture, our patient had achieved equal leg lengths, had normal knee function, and was disease free. CONCLUSIONS: DF resulting in pathological fracture of the midshaft femur is extremely rare and has not been reported to occur in the femoral diaphysis. This location is important as preservation of the joint above and below is preferable and en bloc excision is recommended. Restoration of bone stock after en bloc excision is difficult and recurrence needs to be monitored.

Desmoplastic fibroblastoma mimicking tenosynovial giant cell tumor encasing a tendon of the foot.

Desmoplastic fibroblastoma is an uncommon, benign fibrous soft tissue tumor that usually occurs in the arms, shoulders, neck, hands, and feet in the fifth to seventh decades of life. In general, it is commonly located in the subcutaneous tissue and skeletal muscle. The authors report an unusual case of a desmoplastic fibroblastoma mimicking tenosynovial giant cell tumor encasing a tendon of the foot in a 72-year-old woman. Ultrasonography revealed an inhomogeneously hypoechoic lobulated soft tissue lesion completely wrapped around the extensor digitorum longus tendon. Color Doppler study revealed increased vascularity in the internal and peripheral portions of the lesion. Magnetic resonance imaging revealed a well-defined, lobulated soft tissue mass encasing the extensor digitorum longus tendon with predominantly isointense signal with some areas of hypointense signal on T1-weighted images, predominantly hyperintense signal with some areas of hypointense signal on T2-weighted images, and inhomogeneous enhancement on fat-suppressed contrast-enhanced T1-weighted images. Surgical excision was performed, and the mass was diagnosed on pathological examination as a desmoplastic fibroblastoma. There has been no previously published radiologic case of a desmoplastic fibroblastoma encasing a tendon of the foot in the literature.

Desmoplastic fibroblastoma of the left upper arm.

An elderly female patient presented to the clinic with a several-week history of a mass in her left upper arm that was tender to the touch. The mass was initially thought to be a schwannoma of the left radial nerve based on imaging and was surgically removed. The pathology report revealed an uncommon diagnosis of desmoplastic fibroblastoma.

Desmoplastic Fibroblastoma in Maxillary Alveolar Bone Mimicking An Odontogenic Lesion: A Novel Case Report with Review of Literature.

Desmoplastic fibroblastoma (Collagenous fibroma) is a rare benign soft tissue tumor that disseminates widely and can be intramuscular or subcutaneously. There are seven reported cases in the oral cavity so far. We reported a novel case of collagenous fibroma that has been found in the anterior part of maxilla in a 58-year-old woman as an intraosseous radiolucent lesion that has been discovered during routine radiography. Histopathologically, spindle and stellate-shaped fibroblasts in a collagen-rich stroma as well as binucleated and multinucleated fibroblasts with prominent nucleoli were seen. Desmoplastic fibroblastoma could be found in jaw bones and excision of the lesion is curative, and no aggressive growth has been reported.

Diagnosis and Differential Diagnosis of Desmoplastic Fibroblastoma by Clinical, Radiological, and Histopathological Analyses.

BACKGROUND: Desmoplastic fibroblastoma (collagenous fibroma) is an uncommon benign soft-tissue tumor, rarely involving bone. It shares some overlapping features with other infiltrate tumors, such as desmoid-type fibromatosis, neurofibroma, and low-grade fibromyxoid sarcoma. The misdiagnosis may cause unnecessary surgical overtreatment, especially for those involving bone. In order to deepen the understanding of the diagnosis and differential diagnosis of desmoplastic fibroblastoma, we planned to analyze the clinical, radiological, and histopathological features and the outcome of desmoplastic fibroblastoma on the basis of case analysis and literature review. METHODS: Sixteen cases were retrieved from the surgical pathology records from May 2011 to April 2016 in the Department of Pathology in Beijing Jishuitan Hospital. Formalin-fixed, paraffin-embedded specimens of 16 cases of desmoplastic fibroblastoma were collected. Hematoxylin and eosin stain and immunohistochemistry were used to observe the histological features of desmoplastic fibroblastoma of soft tissue and bone. The images for diagnosis obtained from the ultrasonic examination, X-ray, magnetic resonance imaging, and computed tomography were used to observe the radiological features. Related literatures were retrieved from the PubMed and CNKI databases. RESULTS: Sixteen cases of desmoplastic fibroblastoma of soft tissue were located in the hand (n = 7), foot (n = 4), upper arm (n = 1), shoulder (n = 1), forearm (n = 2), and one case occurred in the proximal femur. Age ranged from 32 to 82 years (median age: 58 years). There were six females and ten males. Histologically, the lesions of soft tissue appeared as well-circumscribed masses with abundant collagenous matrix and low vascularity. Tumor cells were stellate- or spindle-shaped and uniformly distributed within the extracellular matrix. In five cases, the desmoplastic fibroblastoma were found to have infiltrated into the skeletal muscle tissue. In one case of desmoplastic fibroblastoma of bone, radiographs revealed osteolytically well-defined lesion. Immunohistochemistry stain showed that vimentin and smooth muscle actin were positive in all cases of desmoplastic fibroblastoma. CONCLUSIONS: Desmoplastic fibroblastoma (collagenous fibroma) has prominent clinical, histopathological, and radiological features. Before the differential diagnosis from other tumors is obtained by thorough analysis and comparison of the similar and different characteristics, the appropriate surgical management and accurate prognosis evaluation could not be delivered to the patient.

Matrix-regulated integrin αvß5 maintains α5ß1-dependent desmoplastic traits prognostic of neoplastic recurrence.

Desmoplasia, a fibrotic mass including cancer-associated fibroblasts (CAFs) and self-sustaining extracellular matrix (D-ECM), is a puzzling feature of pancreatic ductal adenocarcinoma (PDACs). Conflicting studies have identified tumor-restricting and tumor-promoting roles of PDAC-associated desmoplasia, suggesting that individual CAF/D-ECM protein constituents have distinguishable tumorigenic and tumor-repressive functions. Using 3D culture of normal pancreatic versus PDAC-associated human fibroblasts, we identified a CAF/D-ECM phenotype that correlates with improved patient outcomes, and that includes CAFs enriched in plasma membrane-localized, active α5ß1-integrin. Mechanistically, we established that TGFß is required for D-ECM production but dispensable for D-ECM-induced naïve fibroblast-to-CAF activation, which depends on αvß5-integrin redistribution of pFAK-independent active α5ß1-integrin to assorted endosomes. Importantly, the development of a simultaneous multi-channel immunofluorescence approach and new algorithms for computational batch-analysis and their application to a human PDAC panel, indicated that stromal localization and levels of active SMAD2/3 and α5ß1-integrin distinguish patient-protective from patient-detrimental desmoplasia and foretell tumor recurrences, suggesting a useful new prognostic tool.

Remodeling of Costochondral Graft After Mandibular Reconstruction.

Mandibular tumors are rare in children. Most mandibular tumors in children are benign and locally aggressive, and some might require resection to prevent recurrence. Mandibular reconstruction after tumor resection in children has been less documented in published studies than mandibular reconstruction in adults. In children, age, the growth potential of the mandible, and the donor site are important factors that must be considered. The costochondral graft is an option for reconstruction of the resected portion of the mandible in children, especially when the resection involves the condyle, owing to its biologic and anatomic similarity to the temporomandibular joint and its regenerative and growth potential. The objective of the present case report is to present the unusual remodeling of a nonvascularized costochondral graft after mandibular resection in a pediatric patient.